ZOJ 3872 Beauty of Array【数学】

最新推荐文章于 2020-10-24 20:40:28 发布

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本文介绍了一种计算所有连续子数组美的总和的方法，其中数组的美定义为数组中所有不同整数的和。文章提供了一个高效的C++实现方案，并通过样例输入输出展示了算法的有效性。

Edward has an array A with N integers. He defines the beauty of an array as the summation of all distinct integers in the array. Now Edward wants to know the summation of the beauty of all contiguous subarray of the array A.

Input:There are multiple test cases. The first line of input contains an integer T indicating the number of test cases. For each test case:

The first line contains an integer N (1 <= N <= 100000), which indicates the size of the array. The next line contains N positive integers separated by spaces. Every integer is no larger than 1000000.

Output:For each case, print the answer in one line.

Sample Input

Sample Output

105
21
38

#include<bits/stdc++.h> 
using namespace std;
typedef long long ll;
#define INF 0x3f3f3f3f
#define Max int(1e5+10)
int pre[Max];
int main(){
    int t;
	scanf("%d",&t);
	while(t--)
	{
		int n,x;
	    memset(pre,0,sizeof pre);
        scanf("%d",&n);
        ll sum1=0,sum2=0;
        for(int i=1;i<=n;i++)
		{
			scanf("%d",&x);
			sum1+=(i-pre[x])*x;
			sum2+=sum1;
			pre[x]=i;
		}	
		printf("%lld\n",sum2);
	}
	return 0; 	  
}